package org.chapter2.helper;

import org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.chapter2.util.CollectionUtil;
import org.chapter2.util.PropsUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * Created by james on 16/1/22.
 */
/*
* 数据库操作助手类
* */
public final class DatabaseHelper {
    private static final Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class);

    private static final ThreadLocal<Connection> CONNECTION_HOLDER ;
    private static final QueryRunner QUERY_RUNNER;
    private static final BasicDataSource DATA_SOURCE;

    static {
        CONNECTION_HOLDER = new ThreadLocal<Connection>();
        QUERY_RUNNER = new QueryRunner();

        Properties conf = PropsUtil.loadProps("config.properties");
        String driver = conf.getProperty("jdbc.driver");
        String url = conf.getProperty("jdbc.url");
        String username = conf.getProperty("jdbc.username");
        String password = conf.getProperty("jdbc.password");

        DATA_SOURCE = new BasicDataSource();
        DATA_SOURCE.setDriverClassName(driver);
        DATA_SOURCE.setUrl(url);
        DATA_SOURCE.setUsername(username);
        DATA_SOURCE.setPassword(password);
    }


    /*
    * 获取数据库连接
    * */
    public static Connection getConnection(){
        Connection conn = CONNECTION_HOLDER.get();
        if (conn == null){
            try {
                conn = DATA_SOURCE.getConnection();
            } catch (SQLException e) {
                LOGGER.error("get connection failure", e);
                throw new RuntimeException(e);
            } finally {
                CONNECTION_HOLDER.set(conn);
            }
        }
        return conn;
    }

    /*
    * 查询实体列表
    * */
    public static <T> List<T> queryEntityList(Class<T> entityClass,String sql,Object... params){
        List<T> entityList;
        try {
            Connection conn = getConnection();
            entityList = QUERY_RUNNER.query(conn,sql,new BeanListHandler<T>(entityClass),params);
        } catch (SQLException e){
            LOGGER.error("query entity list failure",e);
            throw new RuntimeException(e);
        }
        return entityList;
    }

    /*
    * 查询实体
    * */
    public static <T> T queryEntity(Class<T> entityClass,String sql,Object... params){
        T entity;
        try {
            Connection conn = getConnection();
            entity = QUERY_RUNNER.query(conn,sql,new BeanHandler<T>(entityClass),params);
        } catch (SQLException e) {
            LOGGER.error("query entity failure",e);
            throw new RuntimeException(e);
        }
        return entity;
    }

    /*
    * 执行查询语句
    * */
    public static List<Map<String,Object>> excuteQuery(String sql,Object... params){
        List<Map<String,Object>> result;
        try {
            Connection conn = getConnection();
            result = QUERY_RUNNER.query(conn,sql,new MapListHandler(),params);
        } catch (SQLException e) {
            LOGGER.error("execute query failure",e);
            throw new RuntimeException(e);
        }
        return result;
    }

    /*
    * 执行更新语句(包括update,insert,delete)
    * */
    public static int executeUpdate(String sql,Object... params){
        int rows = 0;
        try {
            Connection conn = getConnection();
            rows = QUERY_RUNNER.update(conn,sql,params);
        } catch (SQLException e) {
            LOGGER.error("execute update failure",e);
            throw new RuntimeException();
        }
        return rows;
    }

    /*
    * 插入实体
    * */
    public static <T> boolean insertEntity(Class<T> entityClass,Map<String,Object> fieldMap){
        if (CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not insert entity; fieldMap is enpty");
            return false;
        }

        String sql = "INSERT INTO "+getTableName(entityClass);
        StringBuffer columns = new StringBuffer("(");
        StringBuilder values = new StringBuilder("(");
        for (String fieldName : fieldMap.keySet()){
            columns.append(fieldName).append(",");
            values.append("?, ");
        }
        columns.replace(columns.lastIndexOf(", "),columns.length(),")");
        values.replace(values.lastIndexOf(", "),values.length(),")");
        sql +=columns+" VALUES "+values;

        Object[] params = fieldMap.values().toArray();
        return executeUpdate(sql,params) == 1;
    }

    /*
    * 更新实体
    * */
    public static <T> boolean updateEntity(Class<T> entityClass, long id,Map<String,Object> fieldMap){
        if (CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not update entity: fieldMap is empty");
            return false;
        }

        String sql = "UPDATE "+getTableName(entityClass)+" SET ";
        StringBuilder columns = new StringBuilder();
        for (String fieldName : fieldMap.keySet()){
            columns.append(fieldName).append("=?, ");
        }
        sql += columns.substring(0,columns.lastIndexOf(", "))+" WHERE id=?";
        List<Object> paramList = new ArrayList<Object>();
        paramList.addAll(fieldMap.values());
        paramList.add(id);
        Object[] params = paramList.toArray();
        return executeUpdate(sql,params) == 1;
    }

    /*
    * 删除实体
    * */
    public static <T> boolean deleteEntity(Class<T> entityClass,long id){
        String sql = "DELETE FROM "+getTableName(entityClass)+" WHERE id=?";
        return executeUpdate(sql,id) == 1;
    }

    private static String getTableName(Class<?> entityClass){
        return entityClass.getSimpleName();
    }
    /*
    * 执行SQL文件
    * */
    public static void executeSqlFile(String filePath){
        InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(filePath);
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        String sql;

        try {
            while ((sql = reader.readLine()) != null){
                executeUpdate(sql);
            }
        } catch (IOException e) {
            LOGGER.error("execute sql file failure",e);
            throw new RuntimeException(e);
        }

    }
}
